Berlain



(No Model.)

J. G..OHAMBERLAIN. HOLDER FOR GOMMUTATOR BRUSHES.

TIP-surf Made . lrP/ET ill-M4 {mg/a1 Ahbm n EVE.

Patented Mar. 11, 1890.

UNITED STATES PATENT OFFICE,

JACOB C. CHAMBERLAIN, OF NEXV YORK, N. Y.

HOLDER FOR COMMUTATOR-BRUSHES.

SPECIFICATION forming part Of Letters Patent No. 423,309, dated March 11,1890.

Application filed May 29, 1889. Serial No. 312,518. (No model.)

.To all whom, it may concern.-

Be it known that I, JACOB CHESTER CHAM- BERLAIN, a citizen of the United States, residing at New York, county and State of New York, have invented new and useful Improvements in the Holders of Commutator-Brushes, of which the following is a specification.

Myinvention relates especially to improvements in the holders of those brushes or ci'irrent-collectors for the commutators of electric motors and dyna'mos which are adapted to operate with equal facility with either a forward or-backward rotation of the armature.

My improvements are directed to prevention or suppression of the obnoxious chattering, piping, or grating noises consequent on intermittent and unequal contact of such brush with the commutator-cylinder.'

The effect of my construction is, first, to hold the brush firmly and equably upon the commutator-cylinder, thus preserving contact and preventing vibration, and, secondly, to deaden or muffle whatever sound arises at the line of said contact.

Referring to the accompanying drawings, which form a part of this specification, Figure 1 is a partly-sectioned side view of a brushholdcr embodying my invention. Fig. 2 is a section on the line 2 2. Fig. 3 is a section on the line 3 3. Fig. 4 represents a modification of the pressing and sound-muffling device.

The dotted lines 1 represent a commutatorcylinder.

2 is a head so secured to the dynamo-frame as to be capable of rotation about a line coincident with the commutator-axis, as customary with such heads. The two extremities of the head being equipped with precisely similar bruslrholders, it is necessary only to describe one of them. An eye 3 receives a bolt 4, which fastens to said head a bracket 5, having customary binding-posts 6 for one of the wire-conductors and A portion of the bracket takes the form of a guide or holder 8, having a rectangular opening for a brush or collector of suitable conducting and refractory material. Said collector is preferably a tablet 9 of graphite or gas-retort carbon, or other form of hard plumbago. The relative dimensions of said tablet and said opening therefor are such that the tablet fits snugly but easily in its said holder, so that, while be ing retained to a radial position on the periphery of the commutator, it can at all times remain seated, squarely thereupon. Hinged to the said bracket at 10 is the pressure-arm 11, which extends in rear and in the plane of the tablet, and is drawn. theretoward by one or more springs 12,whose ends are secured to the bracket and the arm, respectively. Hinged to said arm at 18, so as to be capable of vibrating in the plane of the tablet, is a piece 14, which I call the rocker. Two sockets or cavities 14 in the under side of this rocker receive and hold a pair of light spiral springs 15 15,which, bearing on the rear edge of the tablet, cause said tablet to press with its en tire length equably and in a regular position on the periphery of thecomiiuitator-cylinder. The said springs l5 15 may be in direct contact with the tablet, but are preferably in contact with and rest upon a copper plate 16, which, itself resting upon the tablet and havingone end screwed fast to the arm 11, serves as a backing to the tablet and to conduct the current in shunt of the supplementary springs 15 15. tween the collector and the holder, constant metallic contact with the collector being assured. The plate 16 further serves to hold the auxiliary springs in place, and this holder when the arm and its attachments are lifted, as for insertion of a new tablet. An important effect of the springs 15 15 and their rocking holder 14 is to deaden or muffle the objectionable grating noise to which these forms of comnuitator brushes are sub ect, while it also, by securinga more equable and constant bruslrcontact,lessens the cause of such sounds and diminishes liabilities to sparking. A hook or lip 17 011 the end of the arm 11 facilitates the lifting of it when desired.

The above described preferred form of my invention is susceptible of various modifications without departing from the essential principles of my invention. For example, an indiaa'ubber pad or cushion 18, attached to a rigid projection 19 20 from the arm 11, may be substituted for the pair of auxiliary springs 15 15" 1 The tablet 9 may be of copper or other suitable conducting material.

I claim 1. The combination of the stationary guide Thusa sure connection is made beat. The combination of the holder proper S, the graphite collector or tablet 9, loosely held and guided therein, the spring-depressed arm 11, its attached rocker 1- the supplementary springs or sound-deadeners 15 15', and the plate-conductor 16, interposed between said souml-deadeners and such tablet, substantially as and for the purposes set forth.

J. O. CHAMBERLAIN.

Witnesses:

HARRY E. KNIGHT, GEO. II. KNIGHT. 

